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digitalmars.D - Using an uninitialized structure

reply B.Schulte <Aldoric gmx.de> writes:
Hi.

I don't get it working. So I ask here.

There is the problem:

CHAR_INFO buffer[];
buffer.length = 100;
foreach( inout CHAR_INFO ci; buffer ) { ci.Char.AsciiChar = ' ';
ci.Attributes=7; }

If I try to compile this (even without the foreach) I get a linker error. The
Linker can't find the __INIT symbol of the CHAR_INFO structure.

Well, sure - there IS NO __init symbol - But I don't WANT to init it somehow
else.

I can't get it working :((

Thanks in advance for every help :)
Sep 03 2007
next sibling parent 0ffh <spam frankhirsch.net> writes:
B.Schulte wrote:

 CHAR_INFO buffer[];


Tried "CHAR_INFO[] buffer;" ?

Regards, Frank
Sep 03 2007
prev sibling next sibling parent reply Regan Heath <regan netmail.co.nz> writes:
B.Schulte wrote:

 Hi.
 
 I don't get it working. So I ask here.
 
 There is the problem:
 
 CHAR_INFO buffer[];
 buffer.length = 100;
 foreach( inout CHAR_INFO ci; buffer ) { ci.Char.AsciiChar = ' ';
ci.Attributes=7; }
 
 If I try to compile this (even without the foreach) I get a linker error. The
Linker can't find the __INIT symbol of the CHAR_INFO structure.
 
 Well, sure - there IS NO __init symbol - But I don't WANT to init it somehow
else.
 
 I can't get it working :((
 
 Thanks in advance for every help :)


Where is the definition of the CHAR_INFO structure?  Have you defined it 
in your code? eg.

import std.c.windows.windows;

extern(C)
{
	struct CHAR_INFO {
	    union _Char {
		WCHAR UnicodeChar;
		CHAR   AsciiChar;
	    }
	    _Char Char;
	    WORD Attributes;
	}
	alias CHAR_INFO* PCHAR_INFO;
}

void main()
{
	CHAR_INFO buffer[];
	buffer.length = 100;
	foreach( inout CHAR_INFO ci; buffer ) { ci.Char.AsciiChar = ' '; 
ci.Attributes=7; }
}

Regan
Sep 03 2007
parent reply B. Schulte <Aldoric gmx.de> writes:
Well, the CHAR_INFO structure is stored in the win32.wincon file. There was
something I took from dsource to use the winAPI methods. 

I didn't want to write in orginal files to fix a problem. I thought about
fixing the problem somewhere else. (Don't modify the wincon.d)

However, it still doesn't work.
Error 42: Symbol Undefined _D5win326wincon9CHAR_INFO6__initZ


There must be some way to use uninitialized variables :(


Regan Heath Wrote:


 
 Where is the definition of the CHAR_INFO structure?  Have you defined it 
 in your code? eg.
 
 import std.c.windows.windows;
 
 extern(C)
 {
 	struct CHAR_INFO {
 	    union _Char {
 		WCHAR UnicodeChar;
 		CHAR   AsciiChar;
 	    }
 	    _Char Char;
 	    WORD Attributes;
 	}
 	alias CHAR_INFO* PCHAR_INFO;
 }
 
 void main()
 {
 	CHAR_INFO buffer[];
 	buffer.length = 100;
 	foreach( inout CHAR_INFO ci; buffer ) { ci.Char.AsciiChar = ' '; 
 ci.Attributes=7; }
 }
 
 Regan
Sep 03 2007
next sibling parent reply Regan Heath <regan netmail.co.nz> writes:
B. Schulte wrote:

 Regan Heath Wrote:
 

 Where is the definition of the CHAR_INFO structure?  Have you defined it 
 in your code? eg.

 import std.c.windows.windows;

 extern(C)
 {
 	struct CHAR_INFO {
 	    union _Char {
 		WCHAR UnicodeChar;
 		CHAR   AsciiChar;
 	    }
 	    _Char Char;
 	    WORD Attributes;
 	}
 	alias CHAR_INFO* PCHAR_INFO;
 }

 void main()
 {
 	CHAR_INFO buffer[];
 	buffer.length = 100;
 	foreach( inout CHAR_INFO ci; buffer ) { ci.Char.AsciiChar = ' '; 
 ci.Attributes=7; }
 }

 Regan


 
 Well, the CHAR_INFO structure is stored in the win32.wincon file. There was
something I took from dsource to use the winAPI methods. 
 
 I didn't want to write in orginal files to fix a problem. I thought about
fixing the problem somewhere else. (Don't modify the wincon.d)
 
 However, it still doesn't work.
 Error 42: Symbol Undefined _D5win326wincon9CHAR_INFO6__initZ
 
 
 There must be some way to use uninitialized variables :(


There is, but I don't believe it has anything to do with the error 
you're getting. :)

You are missing a symbol, the symbol you are missing is mangled in such 
a way that it is clear that it is a D symbol, which means you have 
defined CHAR_INFO as a D struct, instead of using extern (C) as I have 
shown you above.

What dsource project is win32.wincon in?  Perhaps CHAR_INFO isn't 
declared as extern (C) in there...

FYI, you can allocate an array of CHAR_INFO structures without 
initialising like this:

CHAR_INFO[500] abuffer = void;

this is a fixed length array however, perhaps not what you want?


Regan
Sep 03 2007
parent reply B. Schulte <Aldoric gmx.de> writes:
Regan Heath Wrote:


 B. Schulte wrote:

 Regan Heath Wrote:
 

 Where is the definition of the CHAR_INFO structure?  Have you defined it 
 in your code? eg.

 import std.c.windows.windows;

 extern(C)
 {
 	struct CHAR_INFO {
 	    union _Char {
 		WCHAR UnicodeChar;
 		CHAR   AsciiChar;
 	    }
 	    _Char Char;
 	    WORD Attributes;
 	}
 	alias CHAR_INFO* PCHAR_INFO;
 }

 void main()
 {
 	CHAR_INFO buffer[];
 	buffer.length = 100;
 	foreach( inout CHAR_INFO ci; buffer ) { ci.Char.AsciiChar = ' '; 
 ci.Attributes=7; }
 }

 Regan


 
 Well, the CHAR_INFO structure is stored in the win32.wincon file. There was
something I took from dsource to use the winAPI methods. 
 
 I didn't want to write in orginal files to fix a problem. I thought about
fixing the problem somewhere else. (Don't modify the wincon.d)
 
 However, it still doesn't work.
 Error 42: Symbol Undefined _D5win326wincon9CHAR_INFO6__initZ
 
 
 There must be some way to use uninitialized variables :(


 
 There is, but I don't believe it has anything to do with the error 
 you're getting. :)
 
 You are missing a symbol, the symbol you are missing is mangled in such 
 a way that it is clear that it is a D symbol, which means you have 
 defined CHAR_INFO as a D struct, instead of using extern (C) as I have 
 shown you above.
 
 What dsource project is win32.wincon in?  Perhaps CHAR_INFO isn't 
 declared as extern (C) in there...
 
 FYI, you can allocate an array of CHAR_INFO structures without 
 initialising like this:
 
 CHAR_INFO[500] abuffer = void;
 
 this is a fixed length array however, perhaps not what you want?
 
 
 Regan


Well, it really wasn't declared as extern(C). But I inserted it and declared it
as extern(C). Don't know why, but it still don't work.

Here is the dsource project:
http://dsource.org/projects/core32
Sep 03 2007
parent reply Regan Heath <regan netmail.co.nz> writes:
B. Schulte wrote:

 Regan Heath Wrote:
 

 B. Schulte wrote:

 Regan Heath Wrote:


 Where is the definition of the CHAR_INFO structure?  Have you defined it 
 in your code? eg.

 import std.c.windows.windows;

 extern(C)
 {
 	struct CHAR_INFO {
 	    union _Char {
 		WCHAR UnicodeChar;
 		CHAR   AsciiChar;
 	    }
 	    _Char Char;
 	    WORD Attributes;
 	}
 	alias CHAR_INFO* PCHAR_INFO;
 }

 void main()
 {
 	CHAR_INFO buffer[];
 	buffer.length = 100;
 	foreach( inout CHAR_INFO ci; buffer ) { ci.Char.AsciiChar = ' '; 
 ci.Attributes=7; }
 }

 Regan


 Well, the CHAR_INFO structure is stored in the win32.wincon file. There was
something I took from dsource to use the winAPI methods. 

 I didn't want to write in orginal files to fix a problem. I thought about
fixing the problem somewhere else. (Don't modify the wincon.d)

 However, it still doesn't work.
 Error 42: Symbol Undefined _D5win326wincon9CHAR_INFO6__initZ


 There must be some way to use uninitialized variables :(


 There is, but I don't believe it has anything to do with the error 
 you're getting. :)

 You are missing a symbol, the symbol you are missing is mangled in such 
 a way that it is clear that it is a D symbol, which means you have 
 defined CHAR_INFO as a D struct, instead of using extern (C) as I have 
 shown you above.

 What dsource project is win32.wincon in?  Perhaps CHAR_INFO isn't 
 declared as extern (C) in there...

 FYI, you can allocate an array of CHAR_INFO structures without 
 initialising like this:

 CHAR_INFO[500] abuffer = void;

 this is a fixed length array however, perhaps not what you want?


 Regan


 
 Well, it really wasn't declared as extern(C). But I inserted it and declared
it as extern(C). Don't know why, but it still don't work.
 
 Here is the dsource project:
 http://dsource.org/projects/core32


I can't see the win32.wincon file in the svn for that project:
http://dsource.org/projects/core32/browser/trunk/core32/win32

I retract my comment about extern (C) I think maybe this has something 
to do with how you're compiling it, the command line you're using.

Regan
Sep 03 2007
parent reply B. Schulte <Aldoric gmx.de> writes:
Regan Heath Wrote:


 B. Schulte wrote:

 Regan Heath Wrote:
 

 B. Schulte wrote:

 Regan Heath Wrote:


 Where is the definition of the CHAR_INFO structure?  Have you defined it 
 in your code? eg.

 import std.c.windows.windows;

 extern(C)
 {
 	struct CHAR_INFO {
 	    union _Char {
 		WCHAR UnicodeChar;
 		CHAR   AsciiChar;
 	    }
 	    _Char Char;
 	    WORD Attributes;
 	}
 	alias CHAR_INFO* PCHAR_INFO;
 }

 void main()
 {
 	CHAR_INFO buffer[];
 	buffer.length = 100;
 	foreach( inout CHAR_INFO ci; buffer ) { ci.Char.AsciiChar = ' '; 
 ci.Attributes=7; }
 }

 Regan


 Well, the CHAR_INFO structure is stored in the win32.wincon file. There was
something I took from dsource to use the winAPI methods. 

 I didn't want to write in orginal files to fix a problem. I thought about
fixing the problem somewhere else. (Don't modify the wincon.d)

 However, it still doesn't work.
 Error 42: Symbol Undefined _D5win326wincon9CHAR_INFO6__initZ


 There must be some way to use uninitialized variables :(


 There is, but I don't believe it has anything to do with the error 
 you're getting. :)

 You are missing a symbol, the symbol you are missing is mangled in such 
 a way that it is clear that it is a D symbol, which means you have 
 defined CHAR_INFO as a D struct, instead of using extern (C) as I have 
 shown you above.

 What dsource project is win32.wincon in?  Perhaps CHAR_INFO isn't 
 declared as extern (C) in there...

 FYI, you can allocate an array of CHAR_INFO structures without 
 initialising like this:

 CHAR_INFO[500] abuffer = void;

 this is a fixed length array however, perhaps not what you want?


 Regan


 
 Well, it really wasn't declared as extern(C). But I inserted it and declared
it as extern(C). Don't know why, but it still don't work.
 
 Here is the dsource project:
 http://dsource.org/projects/core32


 
 I can't see the win32.wincon file in the svn for that project:
 http://dsource.org/projects/core32/browser/trunk/core32/win32
 
 I retract my comment about extern (C) I think maybe this has something 
 to do with how you're compiling it, the command line you're using.
 
 Regan


Sorry, I was wrong. Here is the official Project page:
http://www.prowiki.org/wiki4d/wiki.cgi?WindowsAPI

However, here is my command line:

compiling:
dmd [files] -c -O -op -D -debug -version=WindowsXP

linking:
dmd [files]
Sep 03 2007
parent Regan Heath <regan netmail.co.nz> writes:
B. Schulte wrote:

 Regan Heath Wrote:
 

 B. Schulte wrote:

 Regan Heath Wrote:


 B. Schulte wrote:

 Regan Heath Wrote:


 Where is the definition of the CHAR_INFO structure?  Have you defined it 
 in your code? eg.

 import std.c.windows.windows;

 extern(C)
 {
 	struct CHAR_INFO {
 	    union _Char {
 		WCHAR UnicodeChar;
 		CHAR   AsciiChar;
 	    }
 	    _Char Char;
 	    WORD Attributes;
 	}
 	alias CHAR_INFO* PCHAR_INFO;
 }

 void main()
 {
 	CHAR_INFO buffer[];
 	buffer.length = 100;
 	foreach( inout CHAR_INFO ci; buffer ) { ci.Char.AsciiChar = ' '; 
 ci.Attributes=7; }
 }

 Regan


 Well, the CHAR_INFO structure is stored in the win32.wincon file. There was
something I took from dsource to use the winAPI methods. 

 I didn't want to write in orginal files to fix a problem. I thought about
fixing the problem somewhere else. (Don't modify the wincon.d)

 However, it still doesn't work.
 Error 42: Symbol Undefined _D5win326wincon9CHAR_INFO6__initZ


 There must be some way to use uninitialized variables :(


 There is, but I don't believe it has anything to do with the error 
 you're getting. :)

 You are missing a symbol, the symbol you are missing is mangled in such 
 a way that it is clear that it is a D symbol, which means you have 
 defined CHAR_INFO as a D struct, instead of using extern (C) as I have 
 shown you above.

 What dsource project is win32.wincon in?  Perhaps CHAR_INFO isn't 
 declared as extern (C) in there...

 FYI, you can allocate an array of CHAR_INFO structures without 
 initialising like this:

 CHAR_INFO[500] abuffer = void;

 this is a fixed length array however, perhaps not what you want?


 Regan


 Well, it really wasn't declared as extern(C). But I inserted it and declared
it as extern(C). Don't know why, but it still don't work.

 Here is the dsource project:
 http://dsource.org/projects/core32


 I can't see the win32.wincon file in the svn for that project:
 http://dsource.org/projects/core32/browser/trunk/core32/win32

 I retract my comment about extern (C) I think maybe this has something 
 to do with how you're compiling it, the command line you're using.

 Regan


 
 Sorry, I was wrong. Here is the official Project page:
 http://www.prowiki.org/wiki4d/wiki.cgi?WindowsAPI


I thought it might be.


 However, here is my command line:
 
 compiling:
 dmd [files] -c -O -op -D -debug -version=WindowsXP
 
 linking:
 dmd [files] 


This works for me:

[charinfo.d]
import std.c.windows.windows;
import win32.wincon;

void main()
{
	CHAR_INFO[] buffer;
	CHAR_INFO[500] abuffer = void;
	buffer.length = 100;
	foreach( inout CHAR_INFO ci; buffer ) { ci.Char.AsciiChar = ' '; 
ci.Attributes=7; }
}

Compiled like so:

E:\D\src\tmp>dmd charinfo.d -c -O -op -D -debug -version=WindowsXP

E:\D\src\tmp>dmd e:\d\win32\win32\wincon.d -c -O -op -D -debug 
-version=WindowsXP

E:\D\src\tmp>dmd charinfo.obj e:\d\win32\win32\wincon.obj
E:\D\dmd\bin\..\..\dm\bin\link.exe 
charinfo+e:\d\win32\win32\wincon,,,user32+kernel32/noi;


Note, this fails giving the error you mentioned because I am not 
compiling and linking with wincon.d:

E:\D\src\tmp>dmd charinfo.d
E:\D\dmd\bin\..\..\dm\bin\link.exe charinfo,,,user32+kernel32/noi;
OPTLINK (R) for Win32  Release 7.50B1
Copyright (C) Digital Mars 1989 - 2001  All Rights Reserved

charinfo.obj(charinfo)
  Error 42: Symbol Undefined _D5win326wincon9CHAR_INFO6__initZ
--- errorlevel 1


If I include it in the compile and link, it works:

E:\D\src\tmp>dmd charinfo.d e:\d\win32\win32\wincon.d
E:\D\dmd\bin\..\..\dm\bin\link.exe charinfo+wincon,,,user32+kernel32/noi;

Regan
Sep 03 2007
prev sibling parent Regan Heath <regan netmail.co.nz> writes:
B. Schulte wrote:

 Regan Heath Wrote:
 

 Where is the definition of the CHAR_INFO structure?  Have you defined it 
 in your code? eg.

 import std.c.windows.windows;

 extern(C)
 {
 	struct CHAR_INFO {
 	    union _Char {
 		WCHAR UnicodeChar;
 		CHAR   AsciiChar;
 	    }
 	    _Char Char;
 	    WORD Attributes;
 	}
 	alias CHAR_INFO* PCHAR_INFO;
 }

 void main()
 {
 	CHAR_INFO buffer[];
 	buffer.length = 100;
 	foreach( inout CHAR_INFO ci; buffer ) { ci.Char.AsciiChar = ' '; 
 ci.Attributes=7; }
 }

 Regan


 Well, the CHAR_INFO structure is stored in the win32.wincon file. There was
something I took from dsource to use the winAPI methods. 
 
 I didn't want to write in orginal files to fix a problem. I thought about
fixing the problem somewhere else. (Don't modify the wincon.d)
 
 However, it still doesn't work.
 Error 42: Symbol Undefined _D5win326wincon9CHAR_INFO6__initZ
 
 
 There must be some way to use uninitialized variables :(
 


I've found win32.wincon here:
http://www.dsource.org/projects/bindings/browser/trunk/win32/wincon.d

Is that the one you used?

I think you had better post your entire source file and the command line 
you are using to compile.

Regan
Sep 03 2007
prev sibling next sibling parent Sean Kelly <sean f4.ca> writes:
B.Schulte wrote:

 Hi.
 
 I don't get it working. So I ask here.
 
 There is the problem:
 
 CHAR_INFO buffer[];
 buffer.length = 100;
 foreach( inout CHAR_INFO ci; buffer ) { ci.Char.AsciiChar = ' ';
ci.Attributes=7; }


Unfortunately, I don't think there's a way to use the "=void" when 
initializing arrays.


Sean
Sep 03 2007
prev sibling parent Walter Bright <newshound1 digitalmars.com> writes:
B.Schulte wrote:

 CHAR_INFO buffer[]; buffer.length = 100; foreach( inout CHAR_INFO ci;
 buffer ) { ci.Char.AsciiChar = ' '; ci.Attributes=7; }
 
 If I try to compile this (even without the foreach) I get a linker
 error. The Linker can't find the __INIT symbol of the CHAR_INFO
 structure.


The init symbol for a struct is placed into the object file generated by 
the source module that defines that struct. In this case, you need to 
link in the compiled module that defines CHAR_INFO.
Sep 03 2007